The_Unforgiven
KoEkWaUs
You understood the question correctly, but your answer isn't correct. I must say it is well thought through, but surely the straw won't move in that direction, since the air is way too fast to eliminate the 'void'
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The_Unforgiven
KoEkWaUs
care to give it another try? Or shall I say it?
Pirate
Emperor
I don't think it will move at all. Sucking creates a low pressure zone inside the straw, air moves into the straw, but the straw does not act to change the direction of the air flow, the vaccuum does. When you turn on a vaccuum hose, the hose doesn't lurch forward, it just sits there. (but turn it to 'blow' and it will whip around like a dragon)
The_Unforgiven
KoEkWaUs
Close enough! Nice job. When blowing, you create a jet, which pushes the straw to the left (conservation of momentum). When sucking you create a pressure minimum, which is 'filled' from all sides, so automatically the momentum equation is satisfied.
RoddyVR
Veteran Board NESer
dont know why, but that just seems realy strange to me.
it seems to add up to 1-1>0 or something.
if you breath throught a straw (in and out) then the straw will move? does that mean that now ignore the straw, and just breath in and out (lets say in space to get rid of gravity, friktion and so on) and you'll move.
just realized you cant breath in in space, but you get what i mean.
how about sitting on one of those rail ways that uses magnetic field to hold you up instead of a rail. where friction is non existatnt. if you just face backwards and breath, you'll speed up?
seems unreal for some reason.....
it seems to add up to 1-1>0 or something.
if you breath throught a straw (in and out) then the straw will move? does that mean that now ignore the straw, and just breath in and out (lets say in space to get rid of gravity, friktion and so on) and you'll move.
just realized you cant breath in in space, but you get what i mean.
how about sitting on one of those rail ways that uses magnetic field to hold you up instead of a rail. where friction is non existatnt. if you just face backwards and breath, you'll speed up?
seems unreal for some reason.....
The_Unforgiven
KoEkWaUs
during breathing out it will move, as discussed. When you stop breathing out it moves back, but this is not dus to breathing in, but due to stopping of breathing out...
Pirate
Emperor
@Roddy: Ok, say your are sitting on your maglev rail breathing. When you breathe in all that acually happens is your diaphram moves downward to make your chest cavity bigger, thus lowering the pressure inside your lungs. The atmosphere does the rest - pressure from all sides forces air into your lungs to fill the vaccuum and equalize the pressure. You don't move because you aren't acting against anything. When you breathe out, you are pushing the air out of your lungs, which is in turn pushing all the air in front of it out of the way. To conserve the momentum of the system, you need to move in the opposite direction from which you are pushing. So you'll start to slide backwards.
Next question: Why do plants grow towards light? I mean, plants don't have brains that say "If I angle myself towards the light I'll get more food." So what is actually happening in the plant?
Next question: Why do plants grow towards light? I mean, plants don't have brains that say "If I angle myself towards the light I'll get more food." So what is actually happening in the plant?
The_Unforgiven
KoEkWaUs
the plant's cells (in the long thing, what' it called) are negatively phototropic (sp?) meaning they grow slower when being subject to more light. that's why it grows towards the light. With it's roots its the fact that the cells are negatively geotropic, meaning they grow into the earth...
RoddyVR
Veteran Board NESer
seems to me that would make them grow AWAY from the sun, not towards it.
The_Unforgiven
KoEkWaUs
nope. The side that gets more light grows slower en hence the flowertop curves TOWARDS the sun
nonconformist
Miserable
The plant hormone, Auxine is released to the opposite side of the plant shoot that is facing the light. This makes the opposite side of the plant grow faster, bending the shoot towards the light.
Pirate
Emperor
That is the closest answer yet, but how does the plant know which side is sunny? That is, how does it know on which side of the plant to release Auxin?
This is what auxin does. It promotes uptake of water in cells, and cell growth and division. Thus the cells with higher concentrations of auxin take up more water and grow faster.
The question remains, what does sunlight do to the plant that makes it grow slower? How does auxin magically concentrate on the sunny side of the plant?
Pirate
Emperor
On second thought, I think what I'm looking for is too small a detail. I had been looking for the insight that auxin is produced equally in all cells, but that sunlight destroys it, thus it appears in higher concentrations on the shady side of a shoot. It's not a concious decision or a complicated chemical process related to photosynthesis.
@nonconformist - So the next question goes to you.
@nonconformist - So the next question goes to you.
nonconformist
Miserable
Thanks, Pirate.
What does a NAND gate do?
What does a NAND gate do?
The Last Conformist
Irresistibly Attractive
A and B are the inputs, C the output:
A B C
0 0 1
0 1 1
1 0 1
1 1 0
A B C
0 0 1
0 1 1
1 0 1
1 1 0
nonconformist
Miserable
Correct my dear confoprmist-who-is-not-a-nonconformist!
Your go!
Your go!
The Last Conformist
Irresistibly Attractive
Time for an easy one (don't use Google!):
A parsec is some 3.262 light years. But how was this specific distance arrived at for use as a unit of length?
A parsec is some 3.262 light years. But how was this specific distance arrived at for use as a unit of length?
Pirate
Emperor
So what is a parallax second? And why can the Millenium Falcon make the Kessel Run in less than 12 of them?
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